11”
6 1/8”
11”
7 5/8”
1 1/2”Maximum
Siding Material
Figure 39: Heli-Fire inlet vent box dimensions.
Installers Information
Combustion Air Intake Restrictor
The air intake restrictor regulates the incoming air fl ow in order to achieve the desired fl ame appearance. The
desired fl ame appearance is one in which the fl ame extends to fi ll the length of the fi rebox (approx. 55”). The
position of the restrictor corresponds to the length of venting between the air intake and the fi rebox. More
airfl ow will be required as the length of venting is increased (to a maximum of 50’) and less airfl ow will be
required if the venting length is shorter. The installer must keep in mind that too much air fl ow will make it
diffi cult for the gas in the fi rebox to be ignited and remain lit, while not enough airfl ow will produce a shorter,
weaker appearance.
To adjust the airfl ow:
1. With the Heli-Fire lit, observe the
length of the fl ame. If fl ame is too
short, allow more airfl ow to enter
the venting by loosening the adjust-
ment screw at the front of the intake
venting and move the screw down-
wards in its slot before tightening
the screw up. This will open the
restrictor. Conversely, if the Heli-
Fire has diffi culty lighting or staying
lit because of a short venting dis-
tance, loosen the adjustment screw
and move the screw upwards in its
slot. This will reduce the airfl ow by
closing the restrictor.
2. Observe the fl ame again. As these
adjustments are guidelines, it may
be necessary for the installer to
repeat the cycle of observation and
adjustment.
Note: The Heli-Fire combustion air inlet box is
used only with the Surface mount power vent
unit. The Flush mount power vent unit has its’
air intake built into it.
Surface Mount Power Vent
RESTRICTOR FLAP
ADJUSTMENT SCREW
RAISE SCREW
TO LOWER THE
RESTRICTOR FLAP
Figure 38: Heli-Fire inlet vent box.
23
5055.64-A
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